Question

x+2y+4=0 3x=-4y-16 simultaneous equation +

Answer 1

Answer:

Writing the system of equations in matrix form AX=B

where A is the 2×2 coefficient matrix, X=(

x

y

) and B is the 2×1 matrix of constants.

Here, A=(

3

2

−2

1

) and B=(

3

16

)

We can write, X=A

−1

B, where

A

−1

=

∣A∣

1

adj(A)

A

−1

=

7

1

×(

1

−2

2

3

)

Substituting the values we get,

(

x

y

)=

7

1

×(

1

−2

2

3

) ×(

3

16

)

(

x

y

)=

7

1

×(

3×1+2×16

(−2)×3+3×16

)

(

x

y

)= (

5

6

).

Hence, x=5 and y=6.

Answer 2

Step-by-step explanation:

X +2Y+

3x+6y=-12

3x +4y=. -16

-____-______+_______

(by substraction)

0+2y =4

y=4/2

y=2

x+2y=-4

X+2×2=-4

X +4. =-4

X=-4 -4

X=- 8